Baylor quarterback Bryce Petty attempts to recover a fumble in the fourth quarter of last week’s game against Oklahoma State in Stillwater, Okla.

STILLWATER, Okla. — Baylor arrived at Oklahoma State seeking its first win in Stillwater since 1939 — and a statement win to validate its case as a national championship contender.

The No. 3 Bears failed in stunning fashion, falling 49-17 in a crushing loss to the No. 11 Cowboys on Saturday night and sending another shockwave through the top of the BCS standings.

The loss for Baylor (9-1, 6-1 Big 12 Conference) almost certainly dooms its national title aspirations, leaving Alabama, Florida State and Ohio State as the remaining unbeatens near the top of the BCS standings. They’ll certainly line up in that order when the new numbers come out Sunday, with the Bears likely no longer in the picture.

Bryce Petty was 28 of 48 passing for 359 yards for Baylor, which had its school-record 13-game winning streak snapped in convincing fashion.

“This is very difficult,” Baylor safety Ahmad Dixon said. “... This hurts. Our chances of still winning the Big 12 aren’t over, but we wanted something bigger than that.

“We wanted something that’s never been done before, and that was to go to a national championship. That dream came down.”

The Bears were done in thanks to Oklahoma State quarterback Clint Chelf’s latest career day against them, a performance that put the Cowboys (10-1, 7-1) within reach of a Big 12 championship.

Chelf passed for a career-high 370 yards and accounted for four touchdowns Saturday. He was 19 of 25 passing and has now thrown for 703 yards in his last two games against Baylor — including last year’s 41-34 loss in Waco.

His latest performance came in a win, a crushing one that delighted the record crowd of 60,218 in Boone Pickens Stadium.

“I couldn’t be more proud of what he’s accomplished,” Oklahoma State coach Mike Gundy said. “He’s been a good leader and he does it quiet. He’s been humbled, and for that he’s had success.”

Oklahoma State has won 10 or more games in three of the last four seasons, and can win the Big 12 by beating rival Oklahoma at home in two weeks.

If Chelf, who lost the starting job earlier this season for the Cowboys, plays like he did on Saturday night against the Sooners, a win is certainly possible.

The senior threw three touchdown passes and ran for a score against the Bears, topping the career day he had against them last year with 333 yards passing. He also had a 48-yard reception and finished with 438 yards of total offense.

Tracy Moore finished with five catches for 126 for Oklahoma State.While the Cowboys had 594 yards of total offense, it was the usually high-flying Bears who were grounded.

Baylor entered Saturday averaging a national-best 61.2 points and 684.8 yards per game, but they had no answers for a Cowboys’ defense that held the high-powered attack in check most of the way.

Oklahoma State forced three Baylor fumbles and also stopped the Bears on two key fourth-down attempts in the second half — both of which led to Cowboys’ touchdowns.

Baylor finished with 453 yards of total offense, and Antwan Goodley had 10 catches for 118 yards receiving.

“(Oklahoma State) played extremely well, played with a lot of energy, made plays when they needed to make plays,” Baylor coach Art Briles said.

After falling behind 35-3, Baylor appeared on the verge of cutting the lead to 35-17 early in the fourth quarter.

However, Petty fumbled after a wild snap deep in Oklahoma State territory and Tyler Patmon returned it 78 yards for a touchdown to put the Cowboys up 42-10.

The score put the exclamation point on a thoroughly one-sided performance.

Chelf lost the starting job earlier this year to sophomore J.W. Walsh, and the senior slowly worked his way back to the role of top option for the Cowboys. He accounted for four touchdowns in last week’s win over Texas, but was at his best Saturday night — capping the stunning performance with a 33-yard touchdown pass to Jhajuan Seales.

As has been the case for most of the season, Gundy didn’t make Chelf available to talk following Saturday’s win. His coach, however, had plenty to say about his recent performances.

“I’m happy with the groove he’s in right now,” Gundy said. “And so, we just want to let him keep going.”

Baylor appeared on its way to the early lead when Petty broke free on a third-and-2 on the Bears’ second possession — with no defenders in his path to the end zone.

However, the quarterback — who entered the game leading the Big 12 in total offense — tripped short of the end zone and fell down at the Oklahoma State 1. Two plays later, Shock Linwood fumbled when he tried to stretch out for the touchdown — with James Castleman knocking the ball loose and recovering for the Cowboys.

That was followed by a 99-yard touchdown drive for Oklahoma State. Kye Staley capped the quick turn of momentum with a 2-yard touchdown run to put the Cowboys up 7-0, a drive that included a 51-yard pass from Chelf to Marcell Ateman.

Oklahoma State pushed its lead to 14-0 in the second quarter when Chelf found Charlie Moore for a 12-yard touchdown over the middle. The completion was Chelf’s 11th-straight of the game.

Chelf didn’t have an incompletion until Oklahoma State’s final possession of the first half, and he finished the half 12 of 13 passing for 238 yards.

“He’s a leader,” Oklahoma State wide receiver Josh Stewart said. “That’s what we want from our quarterback, and he gives us everything we need.”

The Cowboys held Baylor to three three-and-outs on seven possessions in the first half. The Bears entered the game having been held to 17 three-and-outs all season, and their three points at halftime was their lowest first-half total since being held scoreless by Oklahoma State in 2011.

“We’ll bounce back from this,” Petty said. “I’m not going anywhere, and we’re not going anywhere. We still have a lot to accomplish.”

No. 23 USC 47, Colorado 29

BOULDER, Colo. — This game came down to talent, not temperature.

“After a couple of plays, I warmed up,” sophomore Javorius Allen said after running for a career-best 145 yards and three touchdowns in No. 23 Southern California’s 47-29 win over Colorado in 29-degree weather.

That’s tied for the second-coldest kickoff in the Trojans’ storied history.

“I’m from Bakersfield, this doesn’t bother me,” said USC quarterback Cody Kessler, who followed Allen into the stands afterward to lead the band in the school’s fight song, “Conquest.”

Allen’s from Tallahassee, Fla., and he had never seen snow before. He went to the piles that were plowed off to the side of the field and his frozen fingers quickly made him regret making his first snowball.

He was eager to get inside and warm up after the game, but he was summoned into the stands to lead the band.

“I was about to run in here, it was cold,” said Allen, who averaged 6.9 yards on his 21 carries.

The only downer for the Trojans was getting left out in the cold in the Pac-12 race as No. 19 Arizona State held off UCLA 38-33 earlier Saturday to clinch the South division. The Buffaloes saw their slim bowl hopes come to an end in what might have been star receiver Paul Richardson’s final home game. He didn’t catch a pass until midway through the third quarter, and by that time, the Buffs trailed by 30.

For much of the night, he was smothered by cornerback Josh Shaw on short underneath routes, unable to get open for even short gains while this was still a game up for grabs.

Richardson broke free and finished with eight catches for 88 yards, including a 5-yard TD grab with 3:19 left that pulled Colorado to 40-29 after the 2-point conversion. That also gave Richardson the school single-season receptions record of 79, besting D.J. Hackett’s 2003 mark of 78.

The Buffs couldn’t recover the onside kick, however, and fullback Soma Vainuku’s 52-yard TD run two plays later sealed it.

Colorado lost for just the second time in 14 home games in sub-30 degree weather at kickoff.

Sefo Liufau’s 38-yard TD toss to Nelson Spruce on the second play of the fourth quarter was Colorado’s first offensive score.

The Trojans have played in a handful of 29-degree games. The only time they played in a colder game was on Nov. 30, 1957, when they lost 40-12 at Notre Dame in 20-degree weather, the last time they had to play in snow.

This time, the snow that blanketed the Front Range earlier in the week was plowed off to the side.

“It wasn’t like it was freezing cold and it was snowing the whole time,” Kessler said. “No, I don’t think it fazed us.”

“I thought it was rather pleasant tonight compared to what we heard it was going to be like,” said interim head coach Ed Orgeron, who is 6-1 heading into next weekend’s showdown against archrival UCLA.

The Trojans had no hangover from their statement win over then-No. 5 Stanford nor did they get caught peeking ahead to the Bruins. They dominated the Buffaloes on every front in building a 37-7 lead. Allen’s two first-half TD runs were sandwiched around Vainuku’s block of Darragh O’Neill’s punt that bounced out of the end zone for a safety.

Dion Bailey’s interception of Liufau’s pass at midfield led to another USC score, this one when Kessler found Nelson Agholor from 20 yards for a touchdown that gave the Trojans a 23-0 halftime lead.

While the Buffaloes gave their fans little to cheer about, senior Colorado cheerleader Ozell Williams wowed the crowd with a dizzying 57 handsprings between the first and second quarters before pulling up at the 5-yard line to gather himself. That’s by far the closest any Buffalo got to the end zone in the first half.

Things changed quickly when Allen was stripped on USC’s first play of the third quarter and safety Jered Bell scooped up the fumble and returned it 31 yards for the score to make it 23-7.

Allen quickly atoned with a 46-yard scamper that set up Randall Telfer’s 10-yard TD catch. Then he took it in untouched from 23 yards to make it 37-7.

Colorado first-year coach Mike MacIntyre took solace in his team’s late push.

“Last (home) game of the year, freezing cold, down, you keep fighting, you keep battling. They were excited. They were pumped up. It wasn’t it was a dead sideline,” he said. “That shows you a lot of internal fortitude. If they keep doing that and keep doing that and keep doing that, good things will eventually happen.”